APPLICATION OF FUNCTIONALIZED SUPERPARAMAGNETIC MESOPOROUS SILICATES ADSORBENTS ON CLOFIBRIC ACID REMOVAL IN WASTEWATER

Abstract

The objective of this research is to investigate clofibric acid (CFA) adsorption mechanism in high and low concentrations (mg/L and µg/L) and effects of hydrophobic and hydrophilic natural organic matter (NOM) fraction in real swine farm wastewater on functionalized superparamegnetic hexagonal mesoporous silicates (HMS-SPs). Three surface functional groups of synthesized HMS-SPs were applied in this study which is silanol, (ethoxysilylpropyl) diehtylenetriamine and 3-mercaptopropyltriethoxysilane group (HMS-SP, 3N-HMS-SP, and M-HMS-SP, respectively). Furthermore, separation efficiency of adsorbent by modified hydrophobicity surface of High Gradient Magnetic Separation filter (HGMS filter) at various flow rate and particle concentration was also investigated. The CFA adsorption reached the equilibrium at 6 hrs and adsorption kinetic and isotherms were well fitted with pseudo-second-order model and Freundlich model, respectively. At pH 5, 3N-HMS-SP had highest CFA adsorption rate and capacity following with HMS-SP and M-HMS-SP respectively. Adsorption of CFA on all surface functional groups was strongly related to hydrogen bonding between CFA and surface functional groups. Furthermore, the hydrophobic NOM fraction had lower effect on CFA adsorption than the hydrophilic NOM fraction by decreasing adsorption capacities due to active surface competition via hydrogen bonding. The breakthrough times of HGMS filter were enhanced by decreasing of flow rate, and particle concentration. However, hydrophobic modified stainless fiber could not enhance the retention of HMS-SP particle, significantly. The highest separation capacity on this research was conducted in flow rate higher than 5 m/hr and 1 g/L of particle concentration.